im gonna have to go with
1.garra
2.sasuke
3.kimimaro
4.naruto
5.neji
6.haku

Garra first becasue of the whole thing with his father trying to kill him that is hands down crazy. Also he has the person he feels as the only one to care for him try to kill him and say he really didnt llike him. Sasuke goes second because he witnessed his own brother who he looked up to kill his parents even though it was a flash back with the sharigan he still saw how they died. Also he is forced into a destiny of revenge. Kimimaro goes third because he was locked up for years with no real human contact then forced to fight and see his whole clan killed. He is then taking in by one of the worst people ever then dies from an unknown illness before he can accomplish what he lives for. Ok heres when it drops of Naruto is here cause off the whole monster thing like garra but he was able to gain friends by acting like a clown. He also gets a family in sasuke, kakashi, sakura, jiraya and iruka. Neji past is messed up because he is the most blessed member in his clan but will always be marked with the cursed seal just because his father was born minutes after his brother making him a branch family member. His father is also sacraficed for the clan and its head family. What really sucks is he never knew his father did this in his own free will and believes the head family sacrificed him till later on of course. Haku is diffrent to me many may disagree but i believe his past wasnt as bad becasue life was regular untill he learned how to use jutsu and right afterwards he meets zabuza so he doesnt go thru the pain as long as the others. Again this is my opinon nothing really sollid lol.